From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 325EFC388F9 for ; Mon, 26 Oct 2020 18:31:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C03722076A for ; Mon, 26 Oct 2020 18:31:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="AvQOhwnb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C03722076A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C117F6B0062; Mon, 26 Oct 2020 14:31:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A8D2A6B006E; Mon, 26 Oct 2020 14:31:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9265E6B0068; Mon, 26 Oct 2020 14:31:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0035.hostedemail.com [216.40.44.35]) by kanga.kvack.org (Postfix) with ESMTP id 56D806B0068 for ; Mon, 26 Oct 2020 14:31:45 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id D1C83181AC9CC for ; Mon, 26 Oct 2020 18:31:44 +0000 (UTC) X-FDA: 77414920128.07.sheet38_461554827275 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id A7CBD1803F9A1 for ; Mon, 26 Oct 2020 18:31:44 +0000 (UTC) X-HE-Tag: sheet38_461554827275 X-Filterd-Recvd-Size: 3555 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Mon, 26 Oct 2020 18:31:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Nxr3mPTUTpTqNHQZgTOz1Cs76dGKRGwiKCi73s14jS4=; b=AvQOhwnb29KFpHetuF8xRT99VV i8gl5AB+jf/uhEqufUz88wxjT/paeS3Rh1DaYQ9NbhHEN+5ZFXil+zW0/etcNn5VlB3/gXu3w9gv5 PJfCafIsc2b7mqgQAl4g79A+WThihEMzUiceLq3ejap/cq/xJ+sUlWzx2um7dJfp12yIOodh7sdYV j4CrWK15YfOYhy0gk92KD//1A16vxbBk04zZPVZGgCYaS85dj5OPTzGt6Lwy8Jse+bYYYEDGUrmj+ jO1TD9NSXQBtno+1QwKSgRkRtrEZqMogO+18xAHjt1uZ0cdvUNZhdXLTftkC5VruphqUw3L6Ki/8c na6JiiGQ==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kX7HS-0002jU-94; Mon, 26 Oct 2020 18:31:42 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , linux-fsdevel@vger.kernel.org Subject: [PATCH 3/9] mm: Return head pages from grab_cache_page_write_begin Date: Mon, 26 Oct 2020 18:31:30 +0000 Message-Id: <20201026183136.10404-4-willy@infradead.org> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20201026183136.10404-1-willy@infradead.org> References: <20201026183136.10404-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This function is only called from filesystems on their own mapping, so no caller will be surprised by getting back a head page when they were expecting a tail page. This lets us remove a call to thp_head() in wait_for_stable_page(). Signed-off-by: Matthew Wilcox (Oracle) --- mm/filemap.c | 12 ++++++++++-- mm/page-writeback.c | 2 +- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 2214a2c48dd1..62bc6affeb70 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3327,15 +3327,23 @@ generic_file_direct_write(struct kiocb *iocb, str= uct iov_iter *from) } EXPORT_SYMBOL(generic_file_direct_write); =20 -/* +/** + * grab_cache_page_write_begin - Find or create a page for buffered writ= es. + * @mapping: The address space we're writing to. + * @index: The index we're writing to. + * @flags: %AOP_FLAG_NOFS to prevent memory reclaim calling the filesyst= em. + * * Find or create a page at the given pagecache position. Return the loc= ked * page. This function is specifically for buffered writes. + * + * Return: The head page found in the cache, or NULL if no page could be + * created (due to lack of memory). */ struct page *grab_cache_page_write_begin(struct address_space *mapping, pgoff_t index, unsigned flags) { struct page *page; - int fgp_flags =3D FGP_LOCK|FGP_WRITE|FGP_CREAT; + int fgp_flags =3D FGP_LOCK|FGP_WRITE|FGP_CREAT|FGP_HEAD; =20 if (flags & AOP_FLAG_NOFS) fgp_flags |=3D FGP_NOFS; diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 7709f0e223f5..3671568d433f 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2849,7 +2849,7 @@ EXPORT_SYMBOL_GPL(wait_on_page_writeback); */ void wait_for_stable_page(struct page *page) { - page =3D thp_head(page); + VM_BUG_ON_PGFLAGS(PageTail(page), page); if (page->mapping->host->i_sb->s_iflags & SB_I_STABLE_WRITES) wait_on_page_writeback(page); } --=20 2.28.0